MICHIGAMME TOWNSHIP, Mich. — Michigan’s first new mine in decades has begun a multi-year tunneling project to reach a second ore deposit.

Toronto-based Lundin Mining Corp. has requested the Michigan Department of Environmental Quality amend Eagle Mine’s Part 632 mining permit to allow the company to finish the tunnel. The second ore body is a high-grade nickel and copper deposit called Eagle East, MLive has reported.

Eagle Mine began constructing the tunnel in July, but needs approval from the environmental quality department in order to advance all the way to Eagle East. The department said the decision to make a “significant” permit amendment requires a stricter public review. It has until mid-March to formally make that call.

Eagle Mine began extracting nickel, copper and other metals from the original deposit in 2014. The second deposit was discovered in 2015, about a mile east of the Eagle Mine site on Escanaba State Forest land in Michigamme Township. It’s about 2,500 feet below the original deposit.

While Eagle Mine is seen as a job creator, environmental groups consider potential sulfide acid drainage from mining a risk to groundwater, the Salmon Trout River and the Yellow Dog River.

“The company was allowed to dig these new tunnels apparently without even obtaining basic things like mineral rights,” said Brad Garmon, director of conservation at the Michigan Environmental Council. “So, what other protections and procedures have been bypassed?”

The tunnel between the two deposits is expected to take up to three years to finish. Johnson said developing Eagle East will extend the mine’s lifespan into 2023.